Section 22.3 (Exam 3) Flashcards
Speciation May Occur through Geographic Isolation or in Sympatry
What are the two types of speciation?
Allopatric and sympatric
Define allopatric speciation.
Populations are separated by a physical barrier
Define sympatric speciation.
Speciation without physical isolation
After allopatric speciation occurs, how are the two new species related to each other?
They are often sister species
Darwin’s finches are an example of what type of speciation?
allopatric
Which of the three types of selection can lead to sympatric speciation?
disruptive selection
What is the most common way sympatric speciation occurs?
polyploidy
Define polyploidy.
duplication of whole sets of chromosomes
What are the two types of polyploidy?
autopolyploidy and allopolyploidy
Define autopolyploidy.
chromosome duplication in a single species
Define allopolyploidy.
Combining chromosomes from two species
Why is polyploidy important in plant evolution?
Increased genetic diversity from more genetic material
Reproductive isolation leads to speciation
How does autopolyploidy occur accidentally?
if two diploid gametes combine
What is the result of autopolyploidy after two diploid gametes combine?
A tetraploid individual
What is yielded if a tetraploid and a diploid mate?
A sterile triploid
